<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>
  <style>
    *{
      margin:0;
      padding:0;
      list-style:none;
      user-select: none;
    }
    body{
      padding:30px;
    }
    ul li label{
      display: block;
      width: 300px;
      height: 60px;
      border:1px solid #ccc;
      text-align: center;
      line-height: 60px;
      font-size: 30px;
    }
    ul li input{
      display: none;
      width: 300px;
      height: 60px;
      border:1px solid #ccc;
      text-align: center;
      line-height: 60px;
      font-size: 30px;
    }
    ul li.editing label{
      display: none;
    }
    ul li.editing input{
      display: block;
    }
  </style>
</head>
<body>
  <ul>
    <li>
      <label>吃饭</label>
      <input type="text" >
    </li>
    <li>
      <label>睡觉</label>
      <input type="text" >
    </li>
    <li>
      <label>打豆豆</label>
      <input type="text" >
    </li>
  </ul>
  <script src="../js/jquery.min.js"></script>
  <script>
    $('label').on('dblclick',function(){
      $(this).hide();
      $(this).next().val($(this).html());
      $(this).next().show().focus();
    })
  </script>
</body>
</html>